#include <iostream>
#include <string>
#include <cmath>
#include <unordered_map>

using namespace std;

bool is_prime(int n) {
  if (n <= 1) {
    return false;
  }
  for (int i = 2; i <= sqrt(n); ++i) {
    if (n % i == 0) {
      return false;
    }
  }
  return true;
}

int find_closest_prime(int n) {
  int increment = 1;
  while (true) {
    if (is_prime(n + increment)) {
      return n + increment;
    }
    if (is_prime(n - increment)) {
      return n - increment;
    }
    increment++;
  }
}

int main() {
  unordered_map<string, char> words_to_digits = {
    {"zero", '0'}, {"one", '1'}, {"two", '2'}, {"three", '3'}, {"four", '4'},
    {"five", '5'}, {"six", '6'}, {"seven", '7'}, {"eight", '8'}, {"nine", '9'}
  };

  string word1, word2, word3;
  cin >> word1 >> word2 >> word3;

  try {
    string number_str = "";
    number_str += words_to_digits.at(word1);
    number_str += words_to_digits.at(word2);
    number_str += words_to_digits.at(word3);

    int number = stoi(number_str);
    cout << find_closest_prime(number) << endl;
  } catch (const out_of_range& e) {
    cout << "Wrong input" << endl;
  }

  return 0;
}
